Along with official and media reports that some soldiers and police even sell weapons and ammunition to the Taliban, the issue illustrates a problem for commanders trying to improve controls on vital supplies like fuel and ammunition.

A senior Afghan officer in the army's technical and weapons branch, who didn't want to be named as he is not authorized to speak publicly, said troops in Helmand and the northern province of Kunduz fired 7,000 artillery shells in May alone.

"We asked army commanders about it and said if each shell killed only one person, we should have 3,500 Taliban dead in each province," he said. "It's very clear they fire aimlessly and collect the shell casings for copper and sell them."

Another officer, a commander in Helmand who arrived in the province six months ago following a clearout of senior officers in the army's 215th corps, estimated that up to 8 out of every 10 soldiers sold ammunition casings.

"One hundred percent, it happens," he said, also speaking anonymously as he was not authorized to talk to the media. "The reason is the lack of a proper logistics system as well as insufficient pay and leave."

Despite recent efforts to improve pay and conditions for Afghan soldiers, morale remains a problem, with many serving for months or even years without leave, earning around $200 a month.

The clearout of senior officers in Helmand was prompted by reports of abuse and corruption, including cases where officers stole soldiers' pay or demanded bribes to allow them to go on leave.

Assessing just how widespread ammunition misuse is and how far the sale of cases involves deliberately or wastefully firing off ammunition rather than collecting spent cartridges from normal operations remains difficult.

The defense ministry declined to provide ammunition usage figures. But at least seven officials in different parts of the government and military said soldiers discharging their weapons purely in order to produce saleable scrap metal was a problem.

The United States spent more than $300 million from its Afghanistan Security Forces Fund on ammunition for Afghan army and police last year, Department of Defense figures show.

In a report from February, Pentagon inspectors said the systems for supplying and maintaining equipment for police and army units were "immature and unreliable". Lack of proper controls raised the likelihood of "misuse, theft, and diversion to unauthorized purposes."

A scandal last year involving rigged fuel contracts increased the pressure for improvements, and more attention is being given to keeping track of ammunition, which NATO officials say is a "top priority".

"Reporting has been sketchy," said Australian army Brigadier Scott Hicks, deputy director of the logistics and maintenance operation within the NATO-led Resolute Support training and assistance mission. "We're getting better at it with fuel and we're working on ammunition at the moment," he said.

FORMS AND PAPERS

Afghan officials acknowledge there have been cases of ammunition misuse, but deny the problem is widespread.

"Several forms and papers have to be filled out to obtain ammunition and there has to be accountability for everything," said Mohammad Radmanish, a defense ministry spokesman.

NATO officers have, however, been trying to move the Afghan army to overhaul its logistics with new computerized systems and more timely reporting from the field that would enable unusual patterns of ammunition use to be spotted more quickly.

In particular, they are trying to get away from Soviet-era supply doctrine, in which supplies are "pushed" out based on centralized estimates of likely needs.

NATO officials say the system, while relatively simple, makes it harder to see when supplies are misused. Instead, they are working to have frontline units "pull" in supplies through requests to headquarters, which must track and forecast the needs of its subordinate units.

However, they face problems convincing some Afghan commanders who are not comfortable with new methods that require more sophisticated systems and place heavy demands on a force where many soldiers are illiterate.

Kenneth Watson, civilian director of Resolute Support's logistics and maintenance training, said more transparency was essential for foreign donors pledging billions of dollars to support Afghan forces.

"As a coalition, we have to have visibility on assets and we have no visibility with a manual-based system," he said.

At the far end of the supply chain, such considerations weigh little for low-paid soldiers with more to worry about than foreign donors.

"Unfortunately it's very difficult to stop," said the commander in Helmand. Sometimes, he said, units can fire off 10,000-20,000 rounds in a single night.

"We'll ask about casualties on our side or in the Taliban, and there isn't even a single injury."

(Reporting by Mirwais Harooni and James Mackenzie, with additional reporting by Mohammad Stanekzai in Lashkar Gah; Editing by Ian Geoghegan)